Nice piccy
I have a fibreglass kit car running a 2 litre pinto engine with road going GT cam and 32/36 Weber. All other parts are standard.
I am increasingly getting the feeling that the engine is pretty sluggish. Most laymen look at it and remark "that should go well with a 2 litre
engine", I'm no mad arse driver, but I remain unimpressed by the acceleration. I'm sure my 1.4 Astra saloon does much better.
Any suggestions?
Give the car a full service including all consumables. ie. New plugs and points. Check the timing and emissions. If you still think it's not playing ball, you'll have to have it tuned to make sure everything is doing what it should!
Check the auto advance mechanism in the distributor hasn't partially seized, very common on Bosch distributors , check for correct dwell angle ,ignition timing, valve clearances and for full throttle any of which will lose power
Has it always been like this or sudden
Is the cam timing correct,tappets not too tight
If so - as already advised , dont try and tune up old parts
The engine has only done 2500 from a rebuild, but it stood unstarted with all ancillaries for 10 years in a car being built by a total of 3 previous
owners over that period.
It was sluggish when first started and after 2000 miles the head gasket blew. I suspect in its history someone forgot the last torquing of the head
when it was first fired up.
Anyway, the head and valves were in good order as were the pistons and bores. I have replaced the cam belt, done the ignition timing, tuned the carb
(air screw) to give a nice golden colour on the plugs and changed the ignition leads. But, nothing seems to make a difference to the sluggishness.
Thanks for the extra things I can check. I think I will also get someone else to drive the car as there's a slim chance its going about as good
as it should.
The only symptoms I have of poor set up is a an occasional running-on of the engine when I turn it off, and an erratic tickover that refuses to tick
over at less than about 900 rpm.
A pinto in good condition will idle smoothly at very low rpm, if you have the cam belt out by a tooth it will do what you describe.
In the ideal world you want to get an adjustable timing pulley and set the camshaft with around 5 degrees advance.
Regards Mark
I agree full service check vac advance on distributor is working poss check cambelt isn't isn't a tooth out poss clean out carb and finally check second choke is opening on full throttle....
quote:what settings have you used for the timing?
done the ignition timing,
I would say 5 to 8 deg before tdc as a starting point.
And when you get it running better get your self a lighter flywheel it will make the engine rev quicker
quote:
Originally posted by ian locostzx9rc2
I would say 5 to 8 deg before tdc as a starting point.
Ime sure pintos are timed vac pipe off
If your setting it with pipe on itll be very retarded
You can check if dizzys advancing by pointing timing gun at the marks and connect/disconnect the pipe to see if the mark moves
It should go well,although ille be amazed if the carbs not holding it back now its been cammed
if the car feels sluggish it doesnt matter if you set it 8 degrees or 10 or with vacuum connected or not.
you can try setting it to 12 or 14 BTDC....but i doubt anything will happen:
as the engine was rebuilt in the past, its likely that the headgasket face on the head was machined, maybe also the block.
so you will never get the valve timing correctly set without a vernier pulley. even a standard engine would profit from it.
i would start to play arround with valve timing. check again the valve clearances
als very important:
if your diff ratio is too high (e.g. a 3.54), plus large wheels this will kill all acceleration.
please tell us the diff ratio, the wheel-size and tyre size?
quote:
Originally posted by alfas
if the car feels sluggish it doesnt matter if you set it 8 degrees or 10 or with vacuum connected or not.
you can try setting it to 12 or 14 BTDC....but i doubt anything will happen:
as the engine was rebuilt in the past, its likely that the headgasket face on the head was machined, maybe also the block.
so you will never get the valve timing correctly set without a vernier pulley. even a standard engine would profit from it.
i would start to play arround with valve timing. check again the valve clearances
als very important:
if your diff ratio is too high (e.g. a 3.54), plus large wheels this will kill all acceleration.
please tell us the diff ratio, the wheel-size and tyre size?
a standard or slightly uprated pinto will not have valve piston contact, even if the cambelt would break
[Edited on 20/5/14 by alfas]
UPDATE
This topic has moved on a bit since last I posted.
The engine has now been returned to a standard camshaft, so everything including the distributor, carb, camshaft, exhaust is nominally standard.
But, the sluggish behaviour still exists, even in first and second gears.
If the timing is set at 8 deg BTDC at tickover with vacuum disconnected, the car starts fine, ticks over well but has very little power when
accelerating, even when 'buzzing' at about 3000 rpm.
If the ign timing is increased a few degrees, the tickover speeds up and remains smooth, and the acceleration begins to pep up a bit.
BUT, at the position where the performance is satisfactory (but not startling) the engine becomes very difficult to turn over when starting. It has
all the symptoms of over advanced ignition with it appearing that the battery hardly has enough power to spin it over.
The vac advance retard is operating and the mechanical bob weights seem OK. Where do I go from here?
[Edited on 7/9/15 by bumpy]
quote:
Originally posted by alfas
if your diff ratio is too high (e.g. a 3.54), plus large wheels this will kill all acceleration.
please tell us the diff ratio, the wheel-size and tyre size?
Sounds overgeared.
quote:
Originally posted by bumpy
quote:
Originally posted by alfas
if your diff ratio is too high (e.g. a 3.54), plus large wheels this will kill all acceleration.
please tell us the diff ratio, the wheel-size and tyre size?
I have a type 9 gearbox, 3.62 diff and 17 inch wheels with low profile tyres. At 70 mph in fifth gear I am pulling just 2500 rpm, so don't expect it to be pulling away well under those conditions.
[Edited on 7/9/15 by bumpy]
quote:
Originally posted by adithorp
Sounds overgeared.
I have the same gearing as you, 3.62 diff, type 9 and used to have 17's. It is fitted with a 1700 x flow. The engine is tuned, around 130bhp I
would imagine and that would easily spin the rear wheels from close to tick over. I would expect that with a pinto and the extra torque(mine has none)
it should still go well. Everyone's opinion on what power is acceptable is different though.
Have you done a compression test? Does the engine Rev cleanly? Fuel pressure good? I would suggest a trip to the rolling road and get the ignition and
fuelling set up.
the earlier the ignition timing the better the combustion and consecutively the better your power
also fuel consumption will profit from that
my x/flow with a 4-speed box does already rev. 400rpm at 60miles with 185/60r13 and a 3,89 diff
it has around 100bhp..but acceleration is equal to my friends 120HP x/flow with bigger wheels and 3,54 diff
the cheapest tuning is a lower diff ratio and/or smaller wheels..Low gears give fast acceleration, high gears give better cruising and higher max.
speed
[Edited on 7/9/15 by alfas]
quote:
Originally posted by alfas
quote:
Originally posted by bumpy
quote:
Originally posted by alfas
if your diff ratio is too high (e.g. a 3.54), plus large wheels this will kill all acceleration.
please tell us the diff ratio, the wheel-size and tyre size?
I have a type 9 gearbox, 3.62 diff and 17 inch wheels with low profile tyres. At 70 mph in fifth gear I am pulling just 2500 rpm, so don't expect it to be pulling away well under those conditions.
[Edited on 7/9/15 by bumpy]
what i estimated months ago: diff-ratio & those monster wheels will kill all acceleration.
so all you have done until know, was a bit of waste of time.
you can re-fit the original camshaft and try to source 13inch wheels with tyres (the total diamter of the new wheels needs to be remarkably smaller than the actual ones)
what size tyres are fitted now?
[Edited on 7/9/15 by alfas]
ok, than diff needs to be changed to something around 4.4 to 4.6
dont know the nearest availble ratio for your specific diff.
is it a sierra diff?
quote:
Originally posted by Adamirish
I have the same gearing as you, 3.62 diff, type 9 and used to have 17's. It is fitted with a 1700 x flow. The engine is tuned, around 130bhp I would imagine and that would easily spin the rear wheels from close to tick over. I would expect that with a pinto and the extra torque(mine has none) it should still go well. Everyone's opinion on what power is acceptable is different though.
Have you done a compression test? Does the engine Rev cleanly? Fuel pressure good? I would suggest a trip to the rolling road and get the ignition and fuelling set up.
if its a sierra diff they end with 3.9 ratio
so still not enough for your demands...means changing wheels.
quote:
Originally posted by alfas
ok, than diff needs to be changed to something around 4.4 to 4.6
dont know the nearest availble ratio for your specific diff.
is it a sierra diff?
quote:
Originally posted by alfas
if its a sierra diff they end with 3.9 ratio
so still not enough for your demands...means changing wheels.
3300 would be moire than right with 70mph...and you would gain a massive amount of acceleration...believe me
but as ford´s original diff ratios end with 3,92 i do not know what i can recommend you. are there aftermarket diff-ratios like 4.1 or 4.4 available
meanwhile?
quote:
Originally posted by alfas
the cheapest tuning is a lower diff ratio and/or smaller wheels..Low gears give fast acceleration, high gears give better cruising and higher max. speed
[Edited on 7/9/15 by alfas]
quote:
Originally posted by bumpy
quote:
Originally posted by Adamirish
I have the same gearing as you, 3.62 diff, type 9 and used to have 17's. It is fitted with a 1700 x flow. The engine is tuned, around 130bhp I would imagine and that would easily spin the rear wheels from close to tick over. I would expect that with a pinto and the extra torque(mine has none) it should still go well. Everyone's opinion on what power is acceptable is different though.
Have you done a compression test? Does the engine Rev cleanly? Fuel pressure good? I would suggest a trip to the rolling road and get the ignition and fuelling set up.
I don't suppose you can remember what revs it pulled at 70mph?
Compression test is fine. The engine revs cleanly when the car is stationary and there is just the hint of a stutter when accelerating hard on the road, but that is not what I define as sluggish.
I used to own a 1600 mk 3 Cortina and that pulled pretty well, by comparison.
Out of interest, would you know what your car weighs? I was basing my opinion on it being a seven type car, forgive me if I've missed it but what car is it?
quote:
Originally posted by Adamirish
Out of interest, would you know what your car weighs? I was basing my opinion on it being a seven type car, forgive me if I've missed it but what car is it?
you have around 30HP less than the MK, additionally 150-200kg more weight and your car is even more overgeared than the MK.
and i doubt that the MK is pulling well with this. its enough for the owner, but thats his point of view.
i´ve driven lots of x/flow powered sevens (mostly live-axled westfield ans sylva´s), compared to the MK those cars are again 100kg lighter and you
could feel instantly if the car had 13inch or 14inch tyres, a 3.54 or a 3.89 diff fitted...and none of those cars pulled well (IMO) with a 3.54 diff,
even with 13inch rims. all those cars had the typical tuning: double 40ies sidedraughts, between 1600 and 1700cc, fast road camshaft, stage 2 or stage
3 heads, balanced, lightend flywheel etc.
anyway.....for your JBA you need to stick in, at least, a 150HP engine for compensating that.
its up to you, but those 17" wheels look a bit too modern on such a "classic" body design (JBA Falcon), additioanlly your suspension
was not really constructed for such size of rims (unsprung weight, wider-rims--wider track--influence on handling and suspension geometry etc)
go down to a classic design 14" wheel with high wall tyres ...and you would have sorted 2 problems:
the engine would pull better
the visual impression of the car would be improved (IMO)
its up to you: if you, under no circumstances, want to change the rims, than you need to find another solution.
you can try a 3,92 diff (IMO it will improve a bit, but will not solve your problem, so its another waste of time and money)
diff´s with a 4.x ratio arent available
an engine with at least 150HP costs money
the problem definately wont be solved by investing 10pound and 2h labour.
you can set 5times the ignition timing, 10 times the valve clearances, 4 times the camshaft timing...the problem is that your car is overgeared,
mainly caused by the rims.
[Edited on 8/9/15 by alfas]
quote:
Originally posted by alfas
you have around 30HP less than the MK, additionally 150-200kg more weight and your car is even more overgeared than the MK.
and i doubt that the MK is pulling well with this. its enough for the owner, but thats his point of view.
i´ve driven lots of x/flow powered sevens (mostly live-axled westfield ans sylva´s), compared to the MK those cars are again 100kg lighter and you could feel instantly if the car had 13inch or 14inch tyres, a 3.54 or a 3.89 diff fitted...and none of those cars pulled well (IMO) with a 3.54 diff, even with 13inch rims. all those cars had the typical tuning: double 40ies sidedraughts, between 1600 and 1700cc, fast road camshaft, stage 2 or stage 3 heads, balanced, lightend flywheel etc.
anyway.....for your JBA you need to stick in, at least, a 150HP engine for compensating that.
its up to you, but those 17" wheels look a bit too modern on such a "classic" body design (JBA Falcon), additioanlly your suspension was not really constructed for such size of rims (unsprung weight, wider-rims--wider track--influence on handling and suspension geometry etc)
go down to a classic design 14" wheel with high wall tyres ...and you would have sorted 2 problems:
the engine would pull better
the visual impression of the car would be improved (IMO)
its up to you: if you, under no circumstances, want to change the rims, than you need to find another solution.
you can try a 3,92 diff (IMO it will improve a bit, but will not solve your problem, so its another waste of time and money)
diff´s with a 4.x ratio arent available
an engine with at least 150HP costs money
the problem definately wont be solved by investing 10pound and 2h labour.
you can set 5times the ignition timing, 10 times the valve clearances, 4 times the camshaft timing...the problem is that your car is overgeared, mainly caused by the rims.
[Edited on 8/9/15 by alfas]
I would put it on a dyno to get a power curve - should quickly tell you if the problem is engine or gearing - if engine get it dyno tuned.
quote:
Originally posted by bumpy
If the ign timing is increased a few degrees, the tickover speeds up and remains smooth, and the acceleration begins to pep up a bit.
BUT, at the position where the performance is satisfactory (but not startling) the engine becomes very difficult to turn over when starting. It has all the symptoms of over advanced ignition with it appearing that the battery hardly has enough power to spin it over.
The vac advance retard is operating and the mechanical bob weights seem OK. Where do I go from here?
Another alternative is to get a phone app dyno - run the car from start on a safe piece of road - see what the zero to 60 time is and what the power
is calculated at - if it's above say 6.5 seconds and below 80 HP get it tuned by someone who knows what they are doing.
[Edited on 8/9/15 by Ivan]
You say GT cam?
Pinto GT engines were to all intents and purposes a standard 2.0 L with better exhaust manifold and a 32/36 Weber, that's it.
If your GT cam is aftermarket Bon Ford then you need to make sure the cam is timed correctly then look at ignition timing after that.
If it's an aftermarket cam it will be stamped on the cam end opposite end to the cam belt.
If it is a higher spec cam than standard to time it up you would need a vernier cam pully or the cam has been timed using the standard setting which
won't help how the engine revs.
Higher duration cams need a higher idle setting, more advance at idle and a quicker ramp from just off idle to 3600rpm
I have done several fast road Pinto's, the cheap option is
Pinto 2.0L injection head
Rhienz 1.3 mm gasket
FR32 cam or equivelant
You should see 130bhp and rev to 7k without issue
And the brakes are definitely not permanently on are they?
quote:
Originally posted by snapper
You say GT cam?
Pinto GT engines were to all intents and purposes a standard 2.0 L with better exhaust manifold and a 32/36 Weber, that's it.
If your GT cam is aftermarket Bon Ford then you need to make sure the cam is timed correctly then look at ignition timing after that.
If it's an aftermarket cam it will be stamped on the cam end opposite end to the cam belt.
If it is a higher spec cam than standard to time it up you would need a vernier cam pully or the cam has been timed using the standard setting which won't help how the engine revs.
Higher duration cams need a higher idle setting, more advance at idle and a quicker ramp from just off idle to 3600rpm
I have done several fast road Pinto's, the cheap option is
Pinto 2.0L injection head
Rhienz 1.3 mm gasket
FR32 cam or equivelant
You should see 130bhp and rev to 7k without issue
summary what you need to check and update us:
check brakes not binding
inform us about the engine-origin (possibly you will find an engine number)
check if the engine is really a 2l (maybe somebody put a 1.6L in?)
check advance curve of dizzy. do you have a strobe timing light? connect it, rev the car and tell us at which rev´s the advance stops and how many
advance you have.
do you know if the car is a single donor car (hence no q-plate)?
than the engine should be from a sierra?
good chance that an injection head is already fitted, but the injections system has been binned due to an easier installation of a downdraught
carb.
what year is the sierra from?
As I pointed out over a year ago Bosche distributors suffer from seizing auto advance mechanism which would give exactly the symptoms you are suffering
quote:
Originally posted by alfas
summary what you need to check and update us:
check brakes not binding
inform us about the engine-origin (possibly you will find an engine number)
check if the engine is really a 2l (maybe somebody put a 1.6L in?)
check advance curve of dizzy. do you have a strobe timing light? connect it, rev the car and tell us at which rev´s the advance stops and how many advance you have.
brakes fine
2L engine fitted
advance seems fine -- dizzy seams fine
so we are back at the beginninmg: overgeared
what year was the sierra?
are you sure its the sierra engine fitted?
was it an injection engine, converted to carbs?
what is the exact model of carb fitted?
So we are back at the beginning: overgeared - looking most likely.
what year was the sierra?
are you sure its the sierra engine fitted?
was it an injection engine, converted to carbs?
what is the exact model of carb fitted?
Easy answer is to borrow a set of wheels that are smaller and yours. Fit them and see if it goes like stink. Surely someone on here lives near you.
quote:
Originally posted by bumpyI can do a rough calculation assuming the dizzy has a diameter of 3"
Circumference is 7.8" which is 360 degrees. Therefore 0.5" equates to an advance of 23 degrees, which added to the initial setting of 10 degrees BTDC gives a total advance of 33 degrees. This seems about right but I will of course check it.
quote:
Originally posted by Irony
Easy answer is to borrow a set of wheels that are smaller and yours. Fit them and see if it goes like stink. Surely someone on here lives near you.
quote:
Originally posted by alfas
so we are back at the beginninmg: overgeared
Thanks Paul.
For me the rolling road is a last resort. Most of the pleasure I get from owning a kit car is the fun of teasing out solutions to a variety of
problems and the joy of fixing them.
I personally would see the use of a rolling road as an admission of failure.
quote:
Originally posted by Irony
Easy answer is to borrow a set of wheels that are smaller and yours. Fit them and see if it goes like stink. Surely someone on here lives near you.
quote:
Originally posted by bumpy
Thanks Paul.
For me the rolling road is a last resort. Most of the pleasure I get from owning a kit car is the fun of teasing out solutions to a variety of problems and the joy of fixing them.
I personally would see the use of a rolling road as an admission of failure.
quote:
Originally posted by bumpy
A friend has offered me the use of his wheels, so this is what I will do.
quote:
Originally posted by Paul Turner
quote:
Originally posted by bumpy
Thanks Paul.
For me the rolling road is a last resort. Most of the pleasure I get from owning a kit car is the fun of teasing out solutions to a variety of problems and the joy of fixing them.
I personally would see the use of a rolling road as an admission of failure.
Its not a failure at all. I enjoy tinkering as much as the next person but I want a car that works not one that I am unhappy with. The rolling road operator can control the engine and make changes and monitor them in a controlled environment. I am not saying its not possible to do this on the road but you still need experience, jets and many hours of testing. This can be done much quicker on a RR so ultimately get to enjoy your car more.
quote:
Originally posted by bumpy
A friend has offered me the use of his wheels, so this is what I will do.
Just remember that its not just the wheel size its the overall diameter of the wheel/tyre package. For example, a 185/70 13 has an overall diameter of about 585mm, a 195/50 15 about 575mm which is smaller despite being on a bigger wheel. You have 17" wheels but do not give the tyre size, with really low profiles they will have a similar diameter.
If the 13" wheels you are borrowing have low profile tyres beware that your sump and other parts of the car may ground and get damaged.
quote:
Originally posted by bumpy
IF I ever changed my wheels it would be to lower the gearing and to improve drive comfort, which is always an issue with light (fibreglass) cars and low profile tyres.
I would head for profiles of 70 or even 80, and yes I know this will affect cornering at the limits, but that's not important to me.
quote:
Originally posted by Paul Turner
quote:
Originally posted by bumpy
IF I ever changed my wheels it would be to lower the gearing and to improve drive comfort, which is always an issue with light (fibreglass) cars and low profile tyres.
I would head for profiles of 70 or even 80, and yes I know this will affect cornering at the limits, but that's not important to me.
What size tyres are on your car now. We can then advise what you would need to fit to lower the gearing substantially.
Fitting 70 or more especially 80 profiles will not lower your gearing, but it will be more comfortable and easier to drive.
quote:
Originally posted by bumpy
Tyre sizes are 205 50/R17
who said that the tachometer does work correctly?
did the builder, former owner or actual owner ever cared that the tacho-drive (gearbox-side) does match with the diff / tyre size??
or was the given speed (70mph) determined by a sat-nav?
quote:
Originally posted by alfas
who said that the tachometer does work correctly?
did the builder, former owner or actual owner ever cared that the tacho-drive (gearbox-side) does match with the diff / tyre size??
or was the given speed (70mph) determined by a sat-nav?
quote:
Originally posted by Paul Turner
quote:
Originally posted by bumpy
Tyre sizes are 205 50/R17
You quoted in an earlier post that you are doing about 2500 rpm at 70mph using 17" wheels, 3.62 diff and a 5 speed type 9, that does not work out unfortunately.
The combination you quote including tyres should result in about 2850rpm at 70 mph, I suspect you have don't have a 3.62 diff.
Changing to 185/70 13 would drop the gearing by approx. 8%. In comparison changing from a 3.62 to a 3.92 drops the gearing by 8%, exactly the same. Changing to an 80 profile will result in very little change.
Changing to a 185/70 13 would drop the car about 1", have you the ground clearance?
But I suspect you have a very high ratio diesel diff in the car and that could be a factor. If that is a fact a change to lower profile tyres and a 3.92 diff will make quite a difference but will not cure any engine set up issues.
You need to sort both.
NEW INFORMATION
I have just tracked down the VIN plate for my Sierra donor car as lots of Google reading insists this identifies the diff ratio fitted to that car.
The VIN plate box labelled Axle has a V in it. This apparently identifies the diff as a 3.33 
[Edited on 9/9/15 by bumpy]
V code is 3.38:1
quote:
Originally posted by adithorp
V code is 3.38:1
quote:
Originally posted by bumpy
Hi Paul
I cant seem to get the same figures that you got for my current set up. Have you taken into account that the 5th gear on a type 9 box introduces a factor of 0.82 between engine revs and prop shaft revs.?
quote:
Originally posted by Paul Turner
quote:
Originally posted by bumpy
Hi Paul
I cant seem to get the same figures that you got for my current set up. Have you taken into account that the 5th gear on a type 9 box introduces a factor of 0.82 between engine revs and prop shaft revs.?
Will keep it simple.
My set up is 3.92 diff, 0.84 5th (BGH type 9) and 185 60 14 tyres - 575mm diameter.
Yours is 3.38 diff, 0.82 5th and 205 50 17 tyres - 637mm diameter.
Mine does 3500rpm approx at 70mph. Checked with a Garmin and the tach is a Stack that has been verified as accurate in the past.
Thus pro rata your rpm would be 2660 at 70 mph.
To be doing 2500rpm at 70 it would need to have a 3.18 approx diff ratio.
quote:
Originally posted by gremlin1234
quote:
Originally posted by bumpyI can do a rough calculation assuming the dizzy has a diameter of 3"
Circumference is 7.8" which is 360 degrees. Therefore 0.5" equates to an advance of 23 degrees, which added to the initial setting of 10 degrees BTDC gives a total advance of 33 degrees. This seems about right but I will of course check it.
2.5" not 3" would give circ of 7.8"
remember also that the distributor runs at half the engine speed
quote:
Originally posted by Paul Turner
If the 13" wheels you are borrowing have low profile tyres beware that your sump and other parts of the car may ground and get damaged.
this is all too confusing:
its a kitcar...so who knows which parts from the donor have been used or not...or meanwhile replaced or not.
jack-up the rear of the car.
mark your propshaft with a white or yellow pen or sticker, the same you do with one rear wheel (tyre)
than you need to rotate (by hand) both (important is BOTH) rear wheels simultaniously 1 revolution and in the same time count the revolutions your
propshaft is doing.
e.g. diff has a ratio of 3.5
1 rev of the wheels will result in 3.5 rev´s of the prop.
I have taken some measurements.
Existing diff on the car measures a ratio of 3.35 (3.38)
Spare diff in back of garage measures 3.92 (3.92).
So everything is looking good for a swap over which will take my revs at 70mph in 5th gear from 2500 to 2900 - much more realistic.
BUT
The push in drive shafts fitted on the car have a diameter at about half distance of 27.6 mm and the push in drive shafts on the spare diff have a
diameter at similar point of 24 mm. Can anyone explain this?
[Edited on 10/9/15 by bumpy]
[Edited on 10/9/15 by bumpy]
I can only take measurement of the drive shafts that are not fitted, but at the 26 splines the diameter is 28.5mm
I suspect that your spare diff and drive shafts are from a 1600 Sierra
only the facts are intersting:
as the drive-shaft measurement isnt the same the diffs are NOT interchangeable.
i dont knowi fthe internals could be swapped...but imo it makes no sense as a sierra diff can be bought cheaper than all the hazzle swapping
ratios..
so you definately need a new diff....but good news....diffs with a ratio like yours are very welcome within the cobra and v8 guys. so you might make a
profit.
not sure if those guys like the push in drive shaft thing or if they prefer diffs with flanges.
Thanks Alfas
The problem seems to be, if I keep my drive shafts that have been refurbished, I need a way of determining if the new diff I buy from say E Bay will
accommodate them.
I am pretty confused by the bewildering options, particularly what seems to be five or six options on the spline numbers.
All I know for certain at present is I need a 7" unit, push in drive shafts and 3.92 ratio.
It doesn't help that sellers just seem to define the ratio and nothing else.
Surely it cant be that complicated.
Should I start a new thread on this?
[Edited on 11/9/15 by bumpy]
a genuine buyer will answer those questions and will take measurements for you.
it might be that you have a uncommon combination of parts, only used on some unpopular sierra models
unfortunately i´m not that expert with sierra diffs....
do you have a scrapyard nearby?
why not use this forum "market-place" --> "wanted"
quote:
Originally posted by alfas
unfortunately i´m not that expert with sierra diffs....
All this info and stuff is really interesting and good but i'm left with a question,
What car do you normally drive?
I'm asking because if you normally drive a 850cc mk2 mini your view of fast acceleration will be very different to a 535 BMW and this will affect
your view of the kit car. There are gains to be had, but you are limited to the 2 litre standard pinto.
quote:
Originally posted by MikeR
All this info and stuff is really interesting and good but i'm left with a question,
What car do you normally drive?
I'm asking because if you normally drive a 850cc mk2 mini your view of fast acceleration will be very different to a 535 BMW and this will affect your view of the kit car. There are gains to be had, but you are limited to the 2 litre standard pinto.
quote:
Originally posted by hkp57
quote:
Originally posted by alfas
unfortunately i´m not that expert with sierra diffs....
Any time I have had a question about Sierra Diffs or Drive shafts I look at the super7thheaven page
Super 7th Heaven
Ditch the pathetic pinto, and fit a big V8
you will not need to change your beloved wheels, nor the diff, of the halfshafts
but you may need to fit a bigger fuel tank